166718579778 has 16 divisors (see below), whose sum is σ = 370485732960. Its totient is φ = 55572859908.

The previous prime is 166718579773. The next prime is 166718579791. The reversal of 166718579778 is 877975817661.

It is not an unprimeable number, because it can be changed into a prime (166718579773) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1543690500 + ... + 1543690607.

It is an arithmetic number, because the mean of its divisors is an integer number (23155358310).

Almost surely, 2^166718579778 is an apocalyptic number.

166718579778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

166718579778 is an abundant number, since it is smaller than the sum of its proper divisors (203767153182).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

166718579778 is a wasteful number, since it uses less digits than its factorization.

166718579778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3087381118 (or 3087381112 counting only the distinct ones).

The product of its digits is 248935680, while the sum is 72.

It can be divided in two parts, 166718 and 579778, that added together give a square (746496 = 864²).

The spelling of 166718579778 in words is "one hundred sixty-six billion, seven hundred eighteen million, five hundred seventy-nine thousand, seven hundred seventy-eight".